This paper critically reviews two studies examining psychological treatments for posttraumatic stress disorder (PTSD). The first study, by Maercker et al. (2006), evaluates cognitive behavioral therapy (CBT) — including writing assignments and social sharing — against a waitlist control condition in adults who experienced motor vehicle accidents. The second study, by Chemtob, Nakashima, and Carlson (2002), examines Eye Movement Desensitization and Reprocessing (EMDR) as a brief treatment for children with PTSD following a hurricane. For each study, the paper summarizes the research design, measures, and statistical findings, then identifies key methodological limitations that affect the validity and interpretability of the conclusions drawn.
The paper demonstrates methodological critique — the ability to evaluate not just whether a study found significant results, but whether the research design actually tested the intended hypothesis. The writer correctly identifies that comparing CBT to a waitlist control only shows CBT is better than no treatment, not that the new techniques add incremental validity over traditional CBT alone. This distinction between a study's stated purpose and what its design can actually support is a core skill in graduate-level research evaluation.
The paper is organized around two distinct studies, each handled in sequence. For each study, the writer first summarizes the purpose, participants, measures, and statistical results, then transitions into a critical evaluation of the design's limitations. This summary-then-critique structure is a standard format for research review assignments and allows the reader to follow the evidence before encountering the evaluative argument.
Maercker et al. (2006) cite research suggesting that motor vehicle accidents (MVAs) are one of the most common events leading to posttraumatic stress disorder (PTSD) in Germany and the United States. While medications can be used to treat some symptoms of PTSD, there are no medications approved to treat the entire spectrum of PTSD symptoms. Cognitive behavioral therapy (CBT) — which typically includes techniques such as exposure and cognitive restructuring — has been empirically demonstrated to be an effective treatment for PTSD. More recent additions to CBT for treating PTSD, such as writing assignments and social sharing, had not yet been fully empirically tested at the time of the study. The researchers therefore performed a randomized controlled placebo study to determine the effectiveness of these additional techniques.
PTSD was determined using Clinician Administered PTSD Scale (CAPS) scores following involvement in an MVA. Participants were then randomly assigned to either a CBT condition or a waitlist control condition (WLC). WLC participants were told that their treatment would begin in two to three months and that they would need to be reassessed periodically. The primary statistical analysis used was the repeated measures ANOVA.
The results were significant: the CBT group demonstrated substantially greater symptom reduction than the WLC group over the course of the study, F(1, 42) = 51.0, p < .001. A categorical analysis using CAPS scores (PTSD/no PTSD) over time indicated that the CBT group had significantly more non-PTSD members at post-treatment, χ²(1, 21) = 3.70, p < .05. Additional analyses measuring depression and related symptoms also showed that the treatment group was significantly improved compared to the WLC. A three-month follow-up using a series of repeated MANOVAs indicated stability in these findings.
The use of a randomized placebo-controlled design is certainly appropriate for a study attempting to determine whether a particular type of therapy is more effective than no treatment. However, the stated purpose of this study was to determine whether new or additional CBT techniques were effective. Given this aim, the control condition should have been divided into two separate groups: a WLC group and a group that received traditional CBT without the newer techniques included.
As designed, the study only confirms that CBT is effective in treating PTSD; it does not establish whether the additional techniques offer any incremental validity over traditional CBT alone. The overall design is therefore flawed with respect to its stated objective. Furthermore, even within the CBT condition, it is unclear which specific techniques were most beneficial. A mixed design incorporating multiple comparison conditions could have provided better insight into the relative contributions of each treatment component.
Chemtob, Nakashima, and Carlson (2002) note that, at the time of their study, only one controlled treatment study of children with PTSD following a natural disaster had been conducted. Their study was designed to examine a brief treatment for PTSD in children in the aftermath of such an event. Participants were children from a prior study who still met PTSD criteria; the precipitating natural disaster was a hurricane in Hawaii that had occurred approximately one year before. The treatment employed was Eye Movement Desensitization and Reprocessing (EMDR), a brief treatment method that incorporates elements of both CBT and psychodynamic therapy. A total of 32 children completed the study.
Outcome measures included the Child Reaction Index (CRI), the Revised Children's Manifest Anxiety Scale (RCMAS), the Children's Depression Inventory (CDI), and child ratings of the helpfulness of the treatment. The study employed a lagged-groups ABA design in which children were measured at baseline, received treatment, and were then measured again following treatment.
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